Do you struggle with uncomfortable digestive systems such as excess bloating, gas, abdominal pain, constipation, diarrhea, nausea, belching, and/or cramping? Do you have nutrient deficiencies or anemia, or have you experienced loss of muscle mass or unwanted weight loss? If so, these can all be potential signs of SIBO, Small Intestinal Bacterial Overgrowth.

SIBO is an abnormal accumulation of normal bacteria in the small intestine. Most of our microbiota (bacteria and other microorganisms that live in our digestive tracts) live in our large intestines. However, sometimes these bacteria migrate upwards to the small intestine where they do not belong. These bacteria are not pathogenic — it is not an infection — but they can cause the uncomfortable symptoms listed above, of which severe bloating/excess gas is a hallmark symptom. Normally, the large intestine is where most of our bacteria convert undigested carbohydrates into gases. With SIBO, this process occurs in the small intestine, causing many of the uncomfortable symptoms listed above. But SIBO can have repercussions beyond digestive distress. It can lead to nutrient deficiencies such as vitamin B12 or iron, as well as the fat-soluble vitamins A, D, and E, increasing the risk for lower bone mineral density and osteoporosis. It can also lead to unintentional weight loss and loss of muscle mass via protein, fat, and carbohydrate malabsorption.

Predisposing Factors

SIBO is multifactorial and has many different risk factors, including the following. (This is not a comprehensive list.): A history of repeated antibiotic use can disrupt the host microbiota. Acid-suppressing medications like antacids or proton-pump inhibitors decrease acid production in the stomach. (Acid acts as a natural antimicrobial and also stimulates peristalsis, the natural muscular contractions in the intestines that propel food along the digestive tract.) Having naturally low stomach acid likewise can increase one’s risk for SIBO for the same reason. Use of painkillers and opioids also can slow transit time, which increases the risk for SIBO. Disruption of proper vagus nerve function — “vagal tone” — is also a causative factor. Prior abdominal surgeries that resulted in scar-tissue adhesions also affect motility, thereby predisposing one towards SIBO. Diets devoid of pre- and probiotics and high in refined carbohydrates also increase one’s risk for SIBO. Last, there is also a link between irritable-bowel syndrome (IBS) and SIBO. If you have IBS, SIBO could be the root cause. As this list implies, SIBO does not appear out of nowhere. If you find out you have SIBO, work with an experienced health care practitioner to find out why.


The gold standard for SIBO testing is an upper-gut aspirate. This method is not often used, however, because it is invasive, expensive, and can lead to both false positives and false negatives. The most common way to test for SIBO is with a breath test (though they are not always one hundred percent accurate). After a special preparatory diet the day before, and after an overnight fast, you drink a sugar solution and breathe into a bag every 15 minutes for two to three hours. The lab will then test the amount of hydrogen and methane gas found in your sample. Since exclusively bacteria make these gases, their presence indicates the bacteria are there. Test interpretation depends on amount of rise in each gas, as well as at what time periods they show up.


SIBO intervention includes an antimicrobial protocol, dietary protocols, and general digestive support as well as lifestyle changes. Prescription antibiotics are available that stay in the intestines and do not act systemically on the body. Different herbal protocols are another option. One study found that a particular herbal protocol was as effective as antibiotics. Many different diets are used to help manage SIBO, including the low-FODMAPs diet, the Specific Carbohydrate Diet, a combination of the two, as well as a few others. Adding general digestive supportive supplements and herbs is often used, including enzymes, ginger, lemon juice, and digestive bitters, among others. Because slow motility is often a contributing factor, adding prokinetics to help speed up transit time can be very helpful. Chewing food thoroughly and spacing out less frequent meals throughout the day also is important. Adding mind-body techniques to help reduce stress can also play a large role in managing SIBO and preventing relapse.

While this is not a comprehensive overview of SIBO, hopefully it has given you some insight into this condition, or perhaps new avenues to pursue or further questions you would like to get answered. Thankfully, more and more health care practitioners are aware of it and armed with tools to help you manage this often-distressing condition. If you are dealing with SIBO, know that there is a high relapse rate; it can sometimes take several rounds before symptoms are under control, so do not give up after one try. This is why finding the root cause is so important, and a great start in preventing it from recurring in the future.

The information provided in this article is intended for general use only and is not to be used in place of medical advice from a licensed health professional.